


you never know what's hiding in the tide pool

by artistsRevival



Series: Merfolk, Humans, and Those In-Between [1]
Category: Homestuck
Genre: Freaky Mermaid Sex, Gill!Karkat, Gill!Kat, Hand Jobs, M/M, Merman Eridan, Merman!Eridan - Freeform, Mutants, Tentacle Dick, aquatic boyfriends, gillkat
Language: English
Status: Completed
Published: 2014-06-02
Updated: 2014-06-02
Packaged: 2018-02-03 02:33:26
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,497
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1727885
Author URL: https://archiveofourown.org/users/artistsRevival/pseuds/artistsRevival
Summary: <blockquote class="userstuff">
              <p>Karkat's had to hide for years, his whole life - but why should he hide from someone who exists outside of civilization as he knows it?</p>
            </blockquote>





	you never know what's hiding in the tide pool

**Author's Note:**

> yep, shippy oneshots are my gig
> 
> stay tuned for more erikar
> 
> EDIT: THIS AU NOW HAS A TAG ON TUMBLR! STAY TUNED FOR UPDATES. TAG: tumblr.com/tagged/meridan-and-gillkat-adventures  
> AUTHOR'S TUMBLR: tavvross.tumblr.com

You're certain you're living one of the weirdest romcoms in existance.

You’ve been with your boyfriend for - what - six months? You’ve never fucked - you mean, he’s sucked you off, but that’s it - and there’s a reason behind that.

He’s a mermaid, and you are a human. Or, so he thinks. 

On this date, you’re going to give him such a surprise, he’ll be fucking speechless. 

You drop yourself down onto your usual rock on the water's edge to wait for him. Anticipation is building in your stomach and throat and it feels a bit like you've been filled with helium. You see a glimmer of purple beneath the water and you steady your breathing as his head breaks the surface. 

"Hey, Kar," he purrs in that aquatic accent, words bubbling over his tongue like the water he breathes. 

"Hey, fishfuck." Your responses are always so kind. 

"I hav-ve nev-ver fucked a fish in my life, thank you," he responds primly. You grin as he pulls himself up onto the rock. His black-and-violet hair glistens and his toned chest gleams and his gills flutter closed. Those same gills ramp up the anticipation in your chest.

"Yeah, anyway, I’ve got a surprise for you. You'd better appreciate it, it - it’s gonna take a fuckload of courage for me to show you." You curl up as he slips a dripping arm around your shoulders. 

"Hehe, sounds excitin'," he replies. "What’s this ’surprise,’ then?" Eridan pulls your face toward his and kisses you. 

"Not so fast, asshole, I’m trying to be dramatic here." You laugh at him and he pouts. His fins flutter. They look like angelfish fins - you call him that occasionally, if only to see him flush a deep purple. Yes, purple, because apparently mermaids have different shades of blood. 

"Alright, Ariel, I’ll show you. Just - don’t get mad or freak out or anything." 

He looks at you quizically with those violet eyes. "W-why w-would I get mad, Kar?" he asks.

"Because I’ve kept this from you this whole time." He’s watching you intently now. You can feel his gaze burning on the back of your head, intensifying as you slip off the rock with a splash into the water. Good thing you left your phone on the shore. 

You hold your breath for a moment. Jesus fuck, you’re actually doing this, aren’t you? You can feel them flutter. 

You’ve worked your whole life to conceal this, your dad telling you to hide them, after taking you home and not talking about your mother, don’t show anyone, because they’ll take you away and use you as a scientific experiment. He’s right, they probably would - but it’s not like Eridan can do that, right? He’s more of a freak than you are, to humans. 

You haven’t worn shorts in thirteen years, since you were three and lived in the country with your dad and your brother Kankri. Kankri, whom though he was an asshole of epic proportions, that you couldn’t get a word to him edgewise through his long rants, you could trust and share everything with, because he was the same as you. 

You shimmy out of your jeans underwater, tossing the soaking things onto the rock beside Eridan. You can feel the dormant mutations stir and rehydrate in the salty water. You toss your shoes up on shore too. 

Eridan’s looking at you even more strangely. Oh, right, he can’t see anything yet. You take a deep breath and lift your shirt off. You hear his gasp as a background noise, nothing compared to the drumming in your ears as your gills flare open and drink in seawater. 

It’s wonderful, you don’t get the chance to do it very often - only when you bathe, and when you take trips out to deserted beaches. You stretch your toes and dive underwater, blinking your secondary eyelids shut and you can hear a small splash through the water as he slips in and swims over to you.

Your toes are webbed and unnaturally long, and your legs are scaled, bright glaring red, from the knee down. You can feel your finger-webbing extending from the grooves in between your fingers. Everything about you is a glaring, #ff0000 red. Even your blood was unnaturally bright, and your half-albinism - you had ginger hair, not white - caused you to have bright red eyes. You got irrationally sick of the colour, sometimes. 

When you open your first layer eyelids, keeping your clear secondaries closed, you can see clearly through the saltwater, you can see Eridan looking at you in bewildered wonder. He’s staring at your fins, on either side of your shoulders, and the tiny ’fins’ that expand in water and can almost count as your ears, almost human but with a few too many spines and more motor control to be quite so. You blush red to the tips of them as they wriggle. Your trachia shuts off and your throat closes, but you can breath and speak through vibrations in the water instead of the air. 

He’s still staring at you, floating over, flicking his glimmering violet tail and ghosting his webbed hands over your earfins. 

"Kar..." he whispers. The sound is strange, muted but amplified. No air comes out. 

"I-" you start, a blub of air coming out before you clear your gills and start again. "Yeah. I’ve had to hide this for my whole life, so, let’s not flip the fuck out right now?" You grin awkwardly. Your trachia flutters dangerously and you almost cough. 

"This - this is fuckin' aw-wesome, you can -" he stops and grins almost hysterically at you. He seals his lips to yours and you push the saltwater in your mouth out. You don’t expect him, however, to start breathing into you. 

It taked you a moment to understand what’s happening. You struggle for a moment, confused, before you start to just... roll with it. You open your trachia and breath in what he’s giving you. It’s... strangely intimate, like a metaphor you don’t know how to sa- oh. It’s a metaphor that just ran a finger over your upper right gill and _holy shit why does that feel so good._

You give an audible squeak. He grins, sharklike teeth skittering down to scrape lightly at your neck and you shudder as he cards gentle, knowing fingers through your gill filaments. You keen. You didn’t know that was a sound you could even _make._ You can feel yourself growing hard in your boxers.

You shakily reach a hand out to run a finger along his shoulder-fins, and he huffs a little gasp out. You’d found this interesting tidbit of fin sensitivity when looking at your aquatic parts in the mirror and messing about with them. It was kind of awkward, but hey, you were twelve. Everything’s awkward at twelve. 

You slide your hand down his side, stroking his gills gently and feeling his slick, aquatic, grey skin under your calloused hands. His scales feel almost silky underwater. 

You slip your hands to his front and almost jump as you feel a patch of his scales shifting upward. The tip of - something - brushes your fingertips and his filtering hitches. You suppose it’s his weird mermaid dick and you twirl the rapidly-unsheathing - shit, tentacle? - between your fingers. It’s scary long, and thick between your fingers, and you moan slightly at the thought of that thing inside you. For now you’re content with feeling it’s ridges and small, soft fins and Jesus he's reaching into your boxers and stroking your dick. 

You choke a little, and he kisses you and does that trading-breath thing again except this time you breath back into him and he shudders and break away. His moan is high and warbly and you forcefully twist his - tentacle? dick? whatever - between your fingers. 

He starts stroking faster, and your breath catches and stops and you give tiny hiccups of sound. He shudders and moans and whimpers against you, and you’re both stroking each other’s gills and fins and this is the best you’ve ever felt, ever. 

You come first, choking on a whimper, and red floods out into the water. You’ve never actually had sex with anyone else because of this strange method of coming, but you're reassured when he cries out and lets a few bubbles float up to the surface. Violet floats out around you and you’re _breathing it in, fuck, why is that so hot,_ and so is he and you’re just basking in each other’s gaze and presence. You’re so madly in love with this douchefin, it’s not even funny. 

You just breath against each other for awhile, and then he pulls away and grins at you. 

"Hey," he says. "Maybe when you mov-ve out of your human dad’s place, you can come liv-ve w-with me," he says.

"Yeah," you whisper, "maybe." 

You lean in and kiss him again, and you don’t come to the surface again for another good five hours, long past sunset.

**Author's Note:**

> i tried, freaky mermaid sex is weird


End file.
